BOTTOM-WATER TEMP °C 
A 
7h 
: \ Tye Autumn — GULF OF MAINE 
Sr WAI Vi" Sreba esa etc] 
aN ca 
\ * jen eres 1 70-71 
7 
Ny SSH — | 69-70 
L SA HM —— || 68-69 
RNG Vv) 67-68 | 
Soi — iv 6-67 | 
(an ad nd P| 
1963 64 65 66 67 68 6 70 7 72aTseee Ts 
Figure 16.—Adjusted mean bottom-water temperatures in the Gulf of 
Maine in subareas I-V during the autumn, 1963-75. 
area I is the smallest of the Gulf divisions, its large 
negative anomaly (—1.2°C) in 1975 (Table 4) accounted 
for much of the decline observed that year for the entire 
Gulf. 
The subarea TCI’s shown in Figure 17 are further evi- 
dence that years of similar mean temperatures do not nec- 
essarily have similar TCI distributions. A good example 
is shown in Subarea V where the observed means from 
1963 to 1967 were all nearly 6.5°C, but the 1963 and 1967 
TCI’s were vastly different from the 1964-66 TCI distri- 
butions. The sharp temperature decline in 1975 in Sub- 
area I was the result of a return of 4°-6°C water that had 
not occurred there since 1967. The absence of water <8°C 
in Subareas IV and V was the major factor contributing 
to the time-series maxima observed for those subareas 
and also for the entire Gulf of Maine during 1974. 
Georges Bank—Autumn.—Autumn _bottom-water 
temperature indices fluctuated widely between years on 
Georges Bank (Fig. 18) with the two highest adjusted 
temperatures observed in 1965 (13.1°C) and 1973 
(12.7°C); lowest adjusted values were observed in 1967 
(10.6°C) and in 1969 and 1970 (10.4° and 10.5°C). The 
largest annual variations were —2.0°C between 1966 and 
1967 and +1.5°C between 1967 and 1968. The 13-yr mean 
of 11.7°C was about 0.5°C warmer than the 1962-72 long- 
term mean reported by Karaulovsky and Sigaev (see 
footnote 2). Data from Schopf (1967) indicate mean 
autumn Georges Bank temperatures of about 12°C in 
1955 and 1961 and 10°C in 1964. 
Based on observed means, the two coldest years (1963 
and 1967) each had about 20% coverage with 4°-6°C 
water, but this was the only similarity of TCI distribu- 
tion in these years (Fig. 19). The two warmest years (1973 
and 1974) and several of the intermediate years had very 
nearly the same TCI distribution. No water >14°C nor 
<8°C was found in the coldest and warmest years, respec- 
tively. 
Subareas of Georges Bank—Autumn.—Adjusted 
bottom-water temperatures clearly show that during the 
autumn Eastern Georges Bank was consistently colder 
than the remainder of the Bank by as much as 4°C while 
Western and Central Georges Bank alternated as the 
warmest subarea (Fig. 20). A warming trend for the lat- 
ter two subareas since 1966 is indicated, but is not ob- 
vious until 1969 on Eastern Georges Bank. All three sub- 
areas exhibited similar increases or decreases of varying 
magnitude except when only Eastern Georges Bank in- 
creased between 1971 and 1972, and only Western 
Georges Bank increased between 1973 and 1974. Positive- 
ly adjusted anomalies for each subarea were recorded in 
1968 and from 1972 to 1975 (Table 5). 
Distributions of TCI’s for the subareas of Georges 
Bank partially explain why the eastern portion was con- 
sistently colder than the western or central portions (Fig. 
21). A large proportion of water <8°C occurred in the 
eastern subarea in most years from 1963 to 1971, while 
very little water >14°C was found there in any year. Con- 
versely, relatively small amounts of this cold water were 
found in the western or central subareas in any year, but 
water >14°C predominated there in many of the warmest 
years. 
As with the other subareas and other seasons in the 
study area, the distributions of TCI’s were not always 
similar during years of similar observed temperature 
means. 
DISCUSSION 
Annual fluctuations in spring and autumn bottom- 
water temperatures in the Gulf of Maine and Georges 
Bank are obviously related to variations in the volume of 
relatively cold or warm water which denote change in the 
composition of these waters. Bigelow (1927) and Colton 
(1968b) concluded that the volume and composition of 
Table 5.—Moan bottem-water temperatures and anomalies for Georges Bank, 1963-75. Adjusted values are shown in parenthesss. 
Subarea 1963 1964 1967 
1968 
1970 1971 1973 1974 
Western 12.0 ae 1 + .6 -1.5 -3.2 + 
(12.3) (+ .2 5) (+ -3) 1.8) (-1.3) 
Central 11.9 ET / 1.4 0 5 -3.0 + 
(12.3) (- .3) -6) (- .5) 9) (-1.3) 
Eastern 9.7 1.8 1.6 +.1 5 =1.3 
(10.0) (+ .5) (-1.1) (- .5) (- .8) (+ .3) (+ 
Entire 11.3 2.3 1.3 + .6 9 rah) 
Bank (11.7) (= .5) (+ .4) (42.4) (+ .9) (-1-1) (+ 
9 
(+ .7) 
-6 
(+ .3) 
- .9 = ne +1.9 +1.3 +1.5 +2.2 + .6 
(-1.1) (- .7) (+1.3) (+ .8) (+ .9) (+1.5) (0) 
- .2 oe) +1.3 + .8 +2.2 +2.0 no 
(- .5) (- .3) (+ .6) (+ .1) (+#2.5) (+#1.3) (+ .2) 
-1.0 =A, cas + .6 +2.1 42.1 +1.0 
(-1.2) (-1-1) (- .3) (| 0) (+1.5) (41.4) (+ .4) 
ad, - .2 +1.1 ar) +2.1 +1.9 + .8 
(-1.3) (-1-2) (0) (- -1) (#10) (+8) (- .1) 
